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-   -   Triplanetary - Landing and Takeoff (http://forums.sjgames.com/showthread.php?t=161650)

 htial 01-18-2019 06:32 AM

Triplanetary - Landing and Takeoff

Hey Everyone,

I'm just trying to confirm the Landing and Takeoff rules.

I've always played it that as long as you're traveling at one hex per turn you can come straight in and land on a planet. No need to enter orbit before landing. But still having to expend a fuel point to get to the planet. Because if the fuel point wasn't spent the gravity arrow would accelerate the ship to the other side of the planet.
The same goes for takeoff. As long as the fuel points are spent, you just keep getting faster away from the planet.

However. Going over the rules with some new players it was suggested that a ship should always enter orbit before landing on, or leaving, a planet. Which would mean two, or more, fuel points are expended for every landing and takeoff.

Thanks in advance for your time and input.

 rlbeaver 02-16-2019 05:39 PM

Re: Triplanetary - Landing and Takeoff

After trying the game for the first time, resulting in several heated discussions on rule interpretation, I can't see any other way than to spend two fuel to get off the planet.

Turn 1 - You leave atmosphere, the gravity of the planet halts your forward momentum.

Option 1:
Turn 2 - you have no movement as you haven't spent any fuel, so you spend your one point to move outward from the planet, however, you have to account for the gravity, so you would cancel your momentum, or alternately you can spend the one point to move left or right. You now have a momentum of 1, and will continue to circle the planet.
Turn 3 - you plan your movment and spend a point of fuel which will give you a momentum of 2 and you will move out of the planet's orbit.

Option 2:
Turn 2 - You have not movement as haven't spent any fuel, so you spend two points (overburn is it?) and you burn away from the planet, however because of the gravity, you only have a momentum of 1

We ran into a number of situations where we could not agree on how to do the movement and then decided to just give up. If at some point someone has more videos or other examples of movement, we'll dust off the game and try again.

 ColBosch 02-17-2019 01:34 PM

Re: Triplanetary - Landing and Takeoff

I started to write out an explanation, but this really is something that is easier to understand if demonstrated. I'll try to shoot a video after work to explain. It really is simple once you get the trick of how gravity and orbits work. Seriously, it's really clever, and it's one of the things I love about the game.

 ColBosch 02-17-2019 10:04 PM

Re: Triplanetary - Landing and Takeoff

Argh. Okay, I can't get this stupid camera to work. So let me try to explain:

"In orbit" isn't really a thing. What's happening is that your ship has a velocity of 1 and is being pulled by gravity every turn. You have to remember that the Astrogation phase is a thing. So, to leave orbit without using Overload, during the Plotting phase mark down first where your ship would move without considering gravity: one hex straight "ahead." Then spend one fuel point to alter course by one hex from there. During the Movement phase, place your ship counter on the hex you chose, then adjust it for the gravity arrow for the hex you left, then draw in the new vector. A little experimentation will reveal you have several choices that will put you in an empty hex with a vector that won't pass through a gravity hex again.

The turn by turn procedure:

Turn 1: During the Astrogation phase, announce that you're taking off. During the Movement phase, move your ship counter from the planet hex to the appropriate gravity hex (remember, you can only launch from a hexside you've landed from - choose wisely at the start of the game!). Don't draw any lines; your velocity is 0. This takes no fuel.
Turn 2: During the Astrogation phase, announce that you're entering orbit. Draw a dashed line from the hex your ship is in to the empty hex that touches both that hex and the one you intend to move into (either clockwise or counter-clockwise around the planet). During the Movement phase, place your ship counter in the next gravity hex and draw a solid line to there. This burns 1 fuel.
Turn 3: During the Astrogation phase, announce that you're leaving orbit. Draw a dashed line to the appropriate empty hex, as for turn 2, then choose a new endpoint, continuing or redrawing the dashed line to that hex. During the Movement phase, move your ship counter to that hex temporarily, then adjust its final position to account for the gravity hex you just left. Draw solid line between the hex you started from and the final, adjusted hex. This costs 1 fuel, and congratulations, you've left orbit and may move about the map freely.

To fully understand and play Triplanetary, you must not skip the Astrogation phase. Moreover, the dry-erase markers are not optional accessories; they are crucial to properly playing the game. Use them! Every turn, start the Astrogation phase by drawing a dashed line to where your ship would move if it neither spends fuel nor is affected by gravity. Then place a dot for where you'll end up if you spend a point of fuel and/or are affected by gravity; feel free to place multiple dots (or just use your fingertip) as you figure things out. Once you've settled on your final endpoint, erase any temporary dots. Don't forget to draw your vector line, as you'll need it to plot next turn's movement.

I find Triplanetary to be an astonishingly elegant system, but you have to throw away all your normal conceptions about how hex-grid movement works. If you stick to the rules and work through the implications, you're going to find a lot of neat tricks in there, without needing hundreds of pages of special cases.

 RogerBW 02-18-2019 03:26 AM

Re: Triplanetary - Landing and Takeoff

Where this gets complex is in the case where you want to launch and leave orbit as quickly as possible.

Turn 1: you launch from the planet to a gravity hex above the planet, and end up at velocity 0. That's fine.

In 2e, on turn 2 you could boost into orbit, or into one of the three non-gravity hexes now accessible to you; in the latter case you'd have velocity 1 because you're not entering a new gravity hex this turn.

In 3e the wording has been changed, and apparently requires you to go into orbit on turn 2 and then break orbit on turn 3. Players have been asking here and on BGG whether this is a deliberate rule change, but to the best of my knowledge there's been no response.

 ColBosch 02-18-2019 03:11 PM

Re: Triplanetary - Landing and Takeoff

Quote:
 Originally Posted by RogerBW (Post 2243870) Where this gets complex is in the case where you want to launch and leave orbit as quickly as possible. Turn 1: you launch from the planet to a gravity hex above the planet, and end up at velocity 0. That's fine. In 2e, on turn 2 you could boost into orbit, or into one of the three non-gravity hexes now accessible to you; in the latter case you'd have velocity 1 because you're not entering a new gravity hex this turn. In 3e the wording has been changed, and apparently requires you to go into orbit on turn 2 and then break orbit on turn 3. Players have been asking here and on BGG whether this is a deliberate rule change, but to the best of my knowledge there's been no response.
It's pretty clearly a deliberate change, since the rules make clear that you have to conform to gravity hexes you moved through in your LAST turn. If you try to move to one of the three open hexes, the gravity of the hex you left will pull you back to an orbit hex. So yes, in the current edition, you have to enter orbit before you can break it (unless you Overburn).

In space rocketry, this could be considered the equivalent of making your gravity turn and circularizing your orbit, a routine all real spacecraft perform, even if they will go on to travel to another celestial body.

 HeatDeath 07-28-2019 05:36 PM

Re: Triplanetary - Landing and Takeoff

Code:

```- - - - T Y - A B Q  - - - - - X F O C Z - - - - - - - E D R  - - - - - S - -```
I think it's actually possible to leave orbit having expended only one point of fuel.

In the above diagram, O is the planet, A, B, C, D, E, and F are gravity hexes surrounding the planet. Q, R, X, and Z are empty hexes in free space just beyond the gravity hexes. S and Y are empty hexes in free space a little farther out.

In the rules as written, a spaceship is launched from the planet surface by booster rockets, resulting in the spaceship having zero velocity and a full fuel load in (for example) hex C. If the spaceship does nothing, it will fall back to the planet in the next turn. So it has to boost. Let's consider its options.
• O - Boosting in the direction of the planet is just an expensive way to commit suicide.
• Z - Boosting in direction Z is an expensive waste of fuel. Your boost plus the gravity arrow in C will put you right back in C with zero velocity.
• Q and R - These are the hexes you actually boost towards to enter orbit. Boosting towards Q, plus the gravity arrow in C, puts you into hex B, with a heading that, combined with B's gravity arrow, will carry you to A, and eventually around the planet in a counter-clockwise 1-hex-per-turn orbit. Similarly, boosting towards R will put you in D on an orbital trajectory.
• B and D - Now here's where things get interesting. We'll consider case D in detail - bear in mind that B is similar, but in the opposite direction.

We boost towards D. That direction, plus the gravity arrow from C, puts us into hex E, with vector C->E, a velocity of 2 hexes per turn (1 "west" plus 1 "southwest", see the compass rose below). By diving obliquely towards the planet we effectively gave ourselves a gravity-assist velocity boost of 1 hex per turn. Which is both realistic and pretty awesome.

On our next turn, this vector would normally carry us to hex S, but recall that in getting to E, we passed through D and E. So we have to add in those gravity arrows. That puts us in hex X, exactly halfway around the planet from where we started. Cool.

So now we're in hex X, with a vector E->X, but we're not quite free and clear of any gravity arrows. Our vector would takes us to hex T, but recall that we passed through hex F to get here. Adding hex F's gravity arrow puts us in hex Y. If we do nothing else (and I've done the math right) we will continue to coast 1 hexes per turn on this vector (1 "northwest"), through hex Y and beyond. We've escaped Earth's (or whatever planet's) orbit using only 1 point of fuel.

Incidentally, if you do this from Earth, you end up heading in the general vicinity of a Mars intercept course, having only spent one point of fuel. Which is pretty nice if you're a transport and you don't have a huge amount of fuel to spare.

Particularly if you want to evade the Corsair that just boosted from Clandestine at the same time!

Code:

```--  --  NW  NE  --  --   --  W  **  E  -- --  --  SW  SE  --  --```

 ColBosch 08-01-2019 04:58 AM

Re: Triplanetary - Landing and Takeoff

Huh. Let me break out the maps and markers and give that a shot.

 Tom H. 08-03-2019 09:18 PM

Re: Triplanetary - Landing and Takeoff

Quote:
 Originally Posted by ColBosch (Post 2277025) Huh. Let me break out the maps and markers and give that a shot.
Yeah, same here.

Interesting post Heat Death.

It's been a while, and I'll have to get back into it.

 Desert Scribe 08-05-2019 10:01 PM

Re: Triplanetary - Landing and Takeoff

Hey Tom. If you're not too far north of Austin, maybe we can get together for a game sometime.

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